下肢静脉曲张的潜在治疗靶点：miRNA-202调控血管平滑肌细胞表型转化的机制研究

Varicose veins in lower extremities is a common disease which may cause severe complications. Phenotype transition of vascular smooth muscle cells (VSMC) turns to be essential for varicosity pathogenesis. MiRNA (miR) is a highly conservative endogenous non-coding RNA, involving in the pathogenesis of most diseases. MiR-202 was differentially expressed between VSMC derived from varicose veins and normal veins. The results of bioinformation analysis showed a target binding of a regulator of VSMC phenotype, PGC-1α by miR-202. Our preliminary investigation showed that: miR-202 expression was upregulated and PGC-1α expression was downregulated in lesion VSMC; miR-202 overexpression boosted VSMC phenotype transition. Therefore, the current study is aimed to: analyze miR-202 expression in VSMC derived from varicose veins of different pathological grades; explore the effect of miR-202 on VSMC proliferation, cell cylce, migration and the expression of phenotype transition markers; use gene over-expression and silence technique to confirm the mechanism of miR-202 regulating phenotype transition via PGC-1α inhibition. The study will uncover the molecular mechanism of varicose veins pathogenesis and provide novel target for it’s early prevention.

下肢静脉曲张是常见病，可引起严重的并发症。研究表明血管平滑肌细胞（VSMC）表型转化是静脉曲张发生中的关键环节。miRNA是一种高度保守的内源性非编码RNA序列，参与了大多数疾病发生过程。预实验发现miR-202在曲张静脉和对照VSMC中差异表达，生物信息学分析结果显示miR-202与表型调控基因PGC-1α靶向结合。预实验发现：在病变的VSMC中miR-202显著上调、PGC-1α显著下调，过表达miR-202促进VSMC表型转化。在预实验基础上，提出科学假说：miR-202通过抑制PGC-1α表达而促进VSMC表型转化参与静脉曲张的发生。本项目拟：研究miR-202对VSMC增殖、迁移以及表型转化标记的调控作用；探索PGC-1α介导的miR-202调控VSMC表型转化的分子机制。本研究有望阐明miR-202参与静脉曲张发生的分子机制，为静脉曲张的防治提供新的治疗靶点。

下肢静脉曲张是临床上的常见病，目前尚无有效的针对早期静脉曲张的干预措施。探究下肢静脉曲张的发生机制，寻找新的治疗靶点，无疑对静脉曲张的早期防治具有重要意义。现有研究显示：分布于中膜内的平滑肌细胞由收缩型向合成型转化是静脉曲张的发生过程中的关键病理改变，抑制这种转化就有可能防治静脉曲张的发生。本研究旨在探讨microRNA (miR)-202是否通过PGC-1α参与VSMC表型转变，从而导致静脉曲张的发生。我们分析了:miR – 202在静脉曲张中的表达规律，miR – 202在血小板生长因子作用下的血管平滑肌细胞中的表达规律，miR – 202对血管平滑肌细胞增殖和迁移的影响。进一步分析了收缩标记物SM-22α、合成标记物波形蛋白和胶原蛋白I和PGC-1α的表达规律，miR – 202对PGC-1α的靶向调控作用。研究结果显示：在静脉曲张和增生性血管平滑肌细胞中miR – 202表达上调、SM-22α表达降低、波形蛋白和胶原蛋白表达增高。转染miR – 202的血管平滑肌细胞的增殖和迁移,而沉默miR – 202则减少血管平滑肌细胞的增殖和迁移。在转染了PGC-1α3’段非翻译区的HEK293细胞中，miR – 202抑制了荧光素酶活性。miR – 202抑制PGC-1α蛋白表达但不影响它的mRNA的表达。PGC-1α介导了血管平滑肌细胞的表型转换。总之通过本研究发现：miR - 202影响通过PGC-1α靶向调控血管平滑肌细胞表型转换导致静脉曲张的发生，从而为静脉曲张治疗提供了新的靶标。